1. Field of the Invention
The invention relates to a conveying capsule for a pneumatic tube conveyor system. The capsule has a capsule body which is open at one end face and a lid is hinged on the capsule body about a transverse pin. The lid has a closure on the side of its peripheral wall opposite from the hinge pin which bears a closure hook engaging into a latching cutout in the capsule body.
2. Description of the Related Art
Prior art conveying capsules of that type are described in Austrian Patent AT 403 032 B. They offer the advantage, as compared with the conventional pneumatic post capsules having a lid that can be pivoted open about a pin parallel to the axis, that after the lid has been swung down, the aperture on the end face of the capsule body is fully exposed and is not overlapped by a peripheral wall extending over half the periphery and forming a conical capsule head together with the peripheral wall of the lid, which likewise extends over half the periphery. Furthermore, handling is facilitated, since the lid closure can be opened and the lid swung down with one hand. The lid closure is formed by an outward-facing closure hook which engages from the interior of the capsule into a latching cutout in the capsule body, in the manner of a snap closure. To open the closure, therefore, it is merely necessary for the tongue forming the closure hook, produced by slits in the edges of the peripheral wall of the lid, to be pivoted inward against the force of its own resilience in order to press the closure hook out of its latching cutout. Because of the tongue which is to be pivoted inward toward the peripheral wall of the lid, however, such a conveying capsule cannot be closed in a liquid-tight manner, so that such conveying capsules are not suitable for the conveying of, for example, liquid samples, although the swing-up lid offers advantages with regard to the insertion and removal of such samples.
Conveying capsules that can be liquid-tightly closed have become known, heretofore, from Austrian Patent AT 394 179 B. There, the lid is removable from the capsule body and can be locked on the body by a bayonet closure. An O-ring is placed in an annular groove at the face end so that, when the bayonet closure is clamped, the O-ring is correspondingly compressed between the lid and the capsule body. The liquid-tight connection and the functional liquid-tightness in that prior art system depends on the presence of the bayonet closure.